Internet audience measurement may be useful for a number of reasons. For example, some organizations may want to be able to make claims about the size and growth of their audiences or technologies. In addition, understanding Internet audience visitation and habits, as well as what the end-user experienced, may be useful in supporting advertising planning, buying, and selling. For example, information and reports on what display advertisements have been delivered to end-users, and whether those advertisements were visible, may be useful to some organizations, such as the organizations paying for or being promoted by the advertisements.